This invention relates disposable absorbent article such as disposable diapers or menstruation pads.
As a liquid-pervious sheet conventionally used in body fluids absorbent article, it is well known to use a nonwoven fabric or porous plastic film partially formed with a plurality of crests and troughs alternately arranged in one direction to shape stretchable bellows or a composite sheet comprising a nonwoven fabric and elastic members secured under tension to the nonwoven fabric to make the composite sheet elastic.
The region of the sheet shaped in bellows has an elasticity in one direction and forms a groove which is concave either in one direction or in the opposite direction depending on the direction in which the region shaped in bellows is depressed. However, it is impossible for such sheet to be stretched in all directions, i.e., a stretchable concave or convex different from the groove can not be formed in a desired region of the sheet.
The composite sheet comprising the nonwoven fabric and the elastic members secured under tension to the nonwoven fabric inevitably generates a plurality of fine gathers which may give the wearer a feeling of discomfort as the gathers come in contact with the wearer""s skin.
It is an object of this invention to provide disposable absorbent article including a liquid-pervious topsheet having an elastically stretchable region adapted to form a concave or convex in a predetermined zone without giving the wearer a feeling of discomfort.
According to this invention, there is provided a disposable absorbent article comprising: a liquid-permeable topsheet; a liquid-impermeable backsheet; a liquid-absorbent core disposed therebetween; and the topsheet being provided at a predetermined location on upper and lower surface thereof with a stretchable region adapted to be stretchable up- and downward with respect to the upper and lower surfaces, the stretchable region being formed by a plurality of pleats undulating from a peripheral edge toward a central zone of the stretchable region.